0-60 135 opinion

[321]

Originally Posted by Garrett

Sorry, but the 335i folk have already reached that limit

I haven't seen a n54 that has maxed out the BPU's and used race gas.. (apparently the guy who cut that ridiculous 60' had a race gas map but that is speculation)

There is a handful of people that are doing turbo swaps

[321]

I know that turbocharging is possible because of the high velocity pulse gases(something ridiculous like 1000ft/sec) I just don't know how much of that energy is eaten by the turbine. I would think it would depend a lot on a/r and the design of the exhaust system.(ie: minimal reversion) The 335i manifolds aren't exactly log style but they definitely are not mandrel so reversion is going to play a role at all rpm's.

Time to search! I love this shit.:drinking:

[321]

sorry OP for mucking it up(a lot)

http://www.1addicts.com/forums/showt...4180#post24180

/hijack

[240M3SRT]

Originally Posted by TESLAASTRO

245s in the rear are pretty beefy....

My buddies 750 hp viper has 335's, thats beefy.

300tq will smoke 245's from a dig, any power upgrades will just make it worse.

[BForbes]

My official 0-60 opinion is now 4.7 seconds.

[kurichan]

Originally Posted by Garrett

Sorry, but the 335i folk have already reached that limit

What limit Garrett?

Do you have any reliable direct information? It seems your information source is from the e90 site... Not the pinnacle of factual sources.

Do you know for certain that the exhaust is the problem?

Do you understand that you don't need dual pipes to get flow?

Dual or single has very little to do with the challenge here.

You're chasing a red herring.

[Garrett]

Originally Posted by kurichan

What limit Garrett?

Do you have any reliable direct information? It seems your information source is from the e90 site... Not the pinnacle of factual sources.

Do you know for certain that the exhaust is the problem?

Do you understand that you don't need dual pipes to get flow?

Dual or single has very little to do with the challenge here.

You're chasing a red herring.

Yeah the fact the DP's are already yielding pretty good number indicated that the 335i stock exhaust is pretty limiting in it's own right.

At 400hp, the exhaust is already retrictive enough to cause a noticible result. If that the case, then at what limit will the 135's more restrictive exhaust, start hampering power gains..?


Dual pipes in not the arguement, but.... since the 335i has dual pipes it has more undisturbed CFM. The overall fluid dynamics are better aswell, so even though it's not that much of a hinderance now... my original question remains.

At what point will the 135i more restrictive exhaust become a noticeble bottleneck..?

I'd think somewhere around 390hp. So, some of us that are looking at a more liberal PROcede mapping, might run into having to replace the exhaust aswell.

:iono:



-Garrett

[djminkin]

Originally Posted by Garrett

Sorry, but the 335i folk have already reached that limit, I am just wondering how much sooner the 135i will encounter it inefficiencies due to the 135i reduced exhaust sytem.

Yes, I believe the exhaust will offset the weight differences between the two, and probably make them about the same. Im looking towards the tunes and performance upgrades that will make this car insanely fast.

[321]

Some custom gearing where first gear ends in 60mph will lower the time.............................................. ........

[kurichan]

Originally Posted by Garrett

Dual pipes in not the arguement

You specifically said it was, but at last, now we are getting somewhere...

At what point will the 135i more restrictive exhaust become a noticeble bottleneck..?

First, we don't KNOW that the 135i has a more restrictive exhaust. We only know that it's not a dual. A correctly designed single can flow just as much as a dual.

So conjecture on this issue is really sort of moot until the car is actually released and people with real tuning experience get their hands on it.

I'd think somewhere around 390hp. So, some of us that are looking at a more liberal PROcede mapping, might run into having to replace the exhaust as well.

How could you possibly even venture a guess on this?

We know literally NOTHING about the exhaust system. It's a shot in the dark...

[kurichan]

Originally Posted by zba857

Some custom gearing where first gear ends in 60mph will lower the time.............................................. ........

A lower final drive will give you quicker times to 60, but it can really screw up your balance. I had a 4.12 on my weekend car which I switched to a 3.88. The car was insanely buzzy with the lower ratio. With the higher ratio, it's much more a pleasure to drive every day, but I have to keep the revvs so much higher to maintain torque when doing performance driving. Anyhow, my point is, don't go changing gear ratios blindly... Make sure you get REALLY good advice when you do something like this. It can change the fundamental nature of the car!

[321]

Originally Posted by kurichan

A lower final drive will give you quicker times to 60, but it can really screw up your balance. I had a 4.12 on my weekend car which I switched to a 3.88. The car was insanely buzzy with the lower ratio. With the higher ratio, it's much more a pleasure to drive every day, but I have to keep the revvs so much higher to maintain torque when doing performance driving. Anyhow, my point is, don't go changing gear ratios blindly... Make sure you get REALLY good advice when you do something like this. It can change the fundamental nature of the car!

Yea I agree completely.. just trying to sew a torn thread back together...

[kurichan]

Originally Posted by zba857

Yea I agree completely.. just trying to sew a torn thread back together...

Yeah - I was trying to help, but got carried away.

Imagine that... ME getting carried away in a post? :biggrin:

[Garrett]

Originally Posted by kurichan

You specifically said it was, but at last, now we are getting somewhere...

First, we don't KNOW that the 135i has a more restrictive exhaust. We only know that it's not a dual. A correctly designed single can flow just as much as a dual.

So conjecture on this issue is really sort of moot until the car is actually released and people with real tuning experience get their hands on it.

How could you possibly even venture a guess on this?

We know literally NOTHING about the exhaust system. It's a shot in the dark...

Hrmm..

We do know.... due to the laws of physics and fluid dynamics.

Thats why I said we aren't specifically talking about dual exhaust, but that math behind it. Because two, 2.5" tubes has more flow than a single 3". We know the 135i doesn't go beyond a 3" exhaust from header back. Unless the stock 335i exhaust has some obcenly horrible flaw, we can safely assume that the laws of Physics are correct.

CFM and FD.






-Garrett

[BMWeber]

Originally Posted by Garrett

Hrmm..

We do know.... due to the laws of physics and fluid dynamics.

Thats why I said we aren't specifically talking about dual exhaust, but that math behind it. Because two, 2.5" tubes has more flow than a single 3". We know the 135i doesn't go beyond a 3" exhaust from header back. Unless the stock 335i exhaust has some obcenly horrible flaw, we can safely assume that the laws of Physics are correct.

CFM and FD.

-Garrett

you don't know. it all depends on the bends of the exhaust and the rectrictions of the muffler/resonators.

the standard formula is 2.2 CFM per hp= no loss from back pressure. straight pipe flows 115 cfm per square inch. 3" straight pipe is good enough for approximately 490 hp. now two 2.5" straight is good for like 820hp. but then you need to take length and number of bends into account on top of the muffler/resonator restriction. Also the duel exhaust is longer and has more bends. there is no way we could know unless we flow tested the two exhausts. but if you could have a 3" exhaust with minimal bends and a shorter length it could easily flow as well as a dual 2.5". do we know the 135i exhaust isn't bigger than 3"?

[kurichan]

Originally Posted by BMWeber

you don't know.

Exactly.

At this point, conjecture about this is just masturbation.

It might feel good, but nothing productive will result.

[Garrett]

Originally Posted by BMWeber

you don't know. it all depends on the bends of the exhaust and the rectrictions of the muffler/resonators.

the standard formula is 2.2 CFM per hp= no loss from back pressure. straight pipe flows 115 cfm per square inch. 3" straight pipe is good enough for approximately 490 hp. now two 2.5" straight is good for like 820hp. but then you need to take length and number of bends into account on top of the muffler/resonator restriction. Also the duel exhaust is longer and has more bends. there is no way we could know unless we flow tested the two exhausts. but if you could have a 3" exhaust with minimal bends and a shorter length it could easily flow as well as a dual 2.5". do we know the 135i exhaust isn't bigger than 3"?

From the photos the 135i, the exhaust doesn't look like the pipes get BIGGER from the headers back. So it's safe to assume that the 135i is the same size dia. Though, thats not stopping BMW from suprizing us.

BTW, the CFM you state is in perfect laminar flow. one 45degree bend will reduce those figures considerably.

A simple observation will sugest the 335i's exhaust will have less turbulance, thus a less restrictive ahaust.





-Garrett

[321]

Originally Posted by Garrett

From the photos the 135i, the exhaust doesn't look like the pipes get BIGGER from the headers back

Your kidding me right?? If you meant the downpipes then look at the pictures again.. The headers are connected to the turbine. If you are compelled to further this exhaust discussion don't you think you should start a thread about it?

[BMWeber]

Originally Posted by Garrett

BTW, the CFM you state is in perfect laminar flow. one 45degree bend will reduce those figures considerably.

A simple observation will sugest the 335i's exhaust will have less turbulance, thus a less restrictive ahaust.

ummmm did you read my post or are you just commenting on the first line. the main point I made is that it all depends on the bends in the pipes and the restriction of the mufflers and resonators. and simple observation? we have not seen a full picture of the 135i exhaust. all we have to go one is some partial pictures taken while the car is on the ground.

[BForbes]

Originally Posted by zba857

Your kidding me right?? If you meant the downpipes then look at the pictures again.. The headers are connected to the turbine. If you are compelled to further this exhaust discussion don't you think you should start a thread about it?

[Garrett]

Originally Posted by BMWeber

ummmm did you read my post or are you just commenting on the first line. the main point I made is that it all depends on the bends in the pipes and the restriction of the mufflers and resonators. and simple observation? we have not seen a full picture of the 135i exhaust. all we have to go one is some partial pictures taken while the car is on the ground.

Logic dictates that the 135i will not have a radical departure in exhaust design from the 335i. The pipes come off the same engine and travel in the same direction almost the same legnth, the only difference is that one is a true dual exhaust.

That alone DOES have it's benifits..!

We know threw physics and fluid dynamics that any time 2 gases meet there is turbulence and back pressure due to this turbulence. How much and what ineffeciencies that set-up has on the 135i is of interest to me.

Strickly from a tuners, aftermarket point of view.... thus it might limit the 135i's ability to garner better performance number while using Dinan or PROcede software.

CFM in the 335i is better. How much or if it's significant is what I am waiting to find out.

Because it will effect the 0~60 times and the performance of a moded 135i.





-Garrett

[321]

Originally Posted by Garrett

We know threw physics and fluid dynamics that any time 2 gases meet there is turbulence and back pressure due to this turbulence. How much and what ineffeciencies that set-up has on the 135i is of interest to me.

http://www.1addicts.com/forums/showthread.php?t=1655

read post #7